Bore plastering trowel



Feb. 20, 1945. H. R. CRANE BORE PLASTERINIGITROWEL Filed May 25, 1943 Patented Feb; 20, 1945 y BORE-YRLAS'IEBING TRoWEL Hubert-R; Crane, Los Angeles; calich licationjm zs, 1943, Serial No iAsspsa i 12'Clairns. (or. 25-33) g This invention isacylindric, trowel adapted rot, use in pressing a desired plastic; to the; bore face of. given conduits; more especially underground or otherwise installed water systemtmains, I Itvhas longbe'en proposed-to ,line water 'main Pipes {With- Qacementitious, self-setting plastic, so

theJifeof the old pipe might bemuch extended wellset, a large .volumeoi water, and the-more. water extruded at the time of plastering th'e. stifier willbe the laidspl'aster and the less likely itwill be to slump in such cases where 'the'applied mass has no supporting. mold-.a s in the lin v ing of.. pipe as here disclosed. Not, onlyis itde sirablel to dehydrate the. plastic at thejtimeit isloeing applied but, further', it isdesired tocompast the solid and firmly interlockthefineingreclients so that, in the 'cas'etof' water; pipe, linings,

with hydraulic'cernent the, common effect of,

formatioriof a chordalbottom bed'of cementie tiousfmaterial can be prevented ormaterially reduced. If the solids in the eement'can be prac tically totally interlocked'inthe compactedlin- 7 ing then the extrudedwaterlwill be toothina mix tomake a hard cementibedin the bottom of theibcre of the laid lining, and, moreover th e qinfllength. Hydraulic cement contains, before excess water can be'dilut'edj and washedaway overjthe lai'd'lining even before it has completely set. u r p The success'of the dehydration depends of course on how and with what it is done. It has been proposed to draga'perforat'ed cylinderalong the laid' lining in a pipe; but it will quicklybe seenthat in such operation the imperfo-rate porv tions of the face of the*cy1inderthe-'surface lying between contiguous perforations will"have a considerable coat of the extruded-=water but this coat will not-be drainedbcauseofabsence of adjacent wayof escape- ,and the consequence is that after the cylinder has passed all of thesurface'water will be lefttoplaterweep from the lining" and carry enough of the-fine-cement to make a rich grout and harden-to form a chordatebedacross the bottom ofthelining passageway;

Itis highly desirable that a considerable length of "the lining be laid and compressed-to'interlock T m t" sc1ids beioreth liningwbel dehy drated;

It is; therefore, objects orthis invention to provide 'a means and a method forovercoming theobjections hereinabove mentioned: Further, an" obj ect" of theainventionis -to pro vm simple, substantial, low-cost and efiijcient apparatus for dispersin r for compacting and for 65Bend= of whicb; isrhitched;anyzsuitablez pullingsorz I '1 soever.

prevent the slumping downof any. noticeable;

lump of'the lining=at-the dehydratingportzareai as could happen if'the plastic-is low in viscositye or if it has 'notbeen compacted enough;

' More specifically, apurpose of thednventioneis to provide a barrel' trowel having. its shell; pro. vided witha peripheral zonehaving a zig;-zagged. opening port feature.- constituting in: efiect. aicoma pletely annular escape way for water.

The invention consistsofcertain advancements;

in the art of plasteringconduitboresassemforth:

in the ensuing descriptionaand having with; the: above, additional objects andadvantages ashere;-. inafter developed, and whose construction;.-com.- bin'ations, and detaiI ofJ means. and the many her of operation, and the method, will. he made manifest in the following description ofitheiherem with illustrative embodiment; ithbeing unclere stood that modifications, variations and adaptam tions may be resorted to within thew'scope; spirit: and principle of the invention as it is morerpa-r-i ticularly claimedin the addendum. v Figure 1 is a sideelevation ofthe tool.-assem;---. bly, as in bore plastering use.

Figure Z'is-an axiaLdetail section. of, the tooll barrel trowel structure. i a v Figures is a cross-section on '1ine:3;- -3 of; Eigezq, Figure 4 is a diagram of amodified formgofi the annularwater-escape 'outletzone. .1

' Figure, 5' is -a: side elevation of circumferential;;

oblique-line creviced 'trowel; I

A pipe P to be 'circumferentially lined lisp chargedin a de'siredinethod with'the plastic'mg terial-in thisinstance ahydraulic cementgQ-im' quantity to make the-ultimate lining-Lu V H 'The tool here shown include .a-.suitable..leader;

or centering spider having set of outwardly."

radiated legs-e2: froma: frontal hub; 3;;suitab'7 ll: rigidly fixed onto a: central shaft ltztoithea-fonez draft line 5. This spider has plural functions; one, is by the broad front face of its legs to aid in dispersing or plowing outwardly the encountered cement,second, to centralize the trowelling body structure of the tool attached rearwardly thereof,three, to enable quick reduction of objectionable channels which it may create as its elongate centering toes drag through that part of the plaster it pushes past and which lies along the bore face of the pipe engaged by the outer face of the toes 6 for centering purpose. While the front face of the legs are broad (at 2a) the toes 6 converge rearwardly in width with the result that the fluid plastic inherently closes the void or channel dug by the tracking toes, or the plastic mass will be forcibly compacted to obliterate the voids, as disclosed shortly.

Fixed on the shaft 4 in a position immediately in the rear of the spider hub 3 is a somewhat elongate core or ram 1 at about the rear end of which the toes 6 terminate. Immediately at the rear end of the ram I is a flaring nose 8 based on the front end of a cylindric dispersing and compacting member 9 which, as it is pulled forward, is the primary means for applying the dispersed plastic in a circumferential lining form on the bore face of the pipe P.

Following the compacting member or body part 9 is a second and preferably somewhat larger cylindric compacting member ID to give the applied lining a greater degree of compression, and if desired, and preferably, the member in is followed by a larger, cylindric compacting member I l and this may have a polished or semi-polished face to very smoothly finish off the face of the plaster lining. It will be seen that as the lining L is more and more compressed that it will stand some load and therefore will act to automatically center the rear end of the tool.

Another distinctive feature of this invention is in the provision of a peculiar device to enable the escape of water extruded under compression forces applied to the wet lining. This device is predicated on the principle that the tool has a circumferential zone apertured in a manner to get the water, extruded by compression, out of the path of operation of the final compacting or compressing portion of the tool so that water once extruded will not be again subjected to forces tending to drive it back into the cement lining.

Or, in other words, the principle is to provide out as much water as may be practical by one or more steps of cylindric trowelling and conveying ofi the water extruded in a separate stream whilst the final compacting and smoothing trowel is at work on the dehydrated lining surface. By this principle and means the serious objection set forth in Scott's U. S. Patent No. 2,293,365, of 1942, is overcome or greatly reduced; the objection being the tendency of the extruded water and cement to collect as sediment and make a chordate bed on the bottom of the plastic lining. This objection is here overcome for the reason that the extruded water is not again pressed into the face of the plastic lining by the operating tool such as seen in Scott's patent and the art cited therein, and especially the Newsom Patents Nos 1,548,161 and 1,629,292. By this tool here disclosed water is extruded and as much as possible of the line cement is pushed into the lining face and compressed therein and the water is run off separately from the final compressing action. In prior art cement spreaders the water was again swashed by the nose of the Spreaders to the lining face and then, after the, spreader had passed by, rivuletted down the sides of the face to make a thick, rich cement mat with a more or less chordal surface.

It is desired to de-water a complete annular zone of the face of the spread lining of plaster, in

. contrast to the old practice of de-watering by means of a peripheral circle of spaced apertures leaving lanes of the surface still heavily charged with the water content, which greatly aggravated the collection of rich cement at the bottom of the lining. Draining of the annular zone is accomplished in the present invention by so aperturing the tool through its body wall that water may pass at every point in a full circle about the cylindric wall, in a zone of desired axial length, into the chamber of the tool, which is made hollow so as to convey oif the extracted water in a path separate from th 'final compacting face of the tool. In Fig. 1, the successive compacting members are shown as separated by a narrow (but variable) zig-zag or serpentine crevice l2 produced between the interlaced saw-tooth formations I3 of the contiguous end edges of the axially adjacent members 9, Ill and II. To make a restrictive passageway against too free a flow of the solids of the plastic cement the forward fac ing sides l3a of some of the teeth are bevelled and underlie the adjacent faces l3b of the opposite, rearwardly pointing teeth of the gangs. Thus a considerable length and area of opening for water escape is presented but at the same time the solids are rejected and sent back to the face of the plastic lining L.

As clearly shown in Fig. 2, the rearwardly facing teeth [3 have right-angled end shoulders l4 and the top faces of the forwardly facing teeth are inclined forwardly and inwardly at [5 whereby to form slight pockets into which the laid plaster may somewhat expand (if so inclined) and in which water may collect on its way to the escape aperture l2. The fine cement collecting on the faces I5 are again forced out to and compressed in the face of the lining L.

Fig. 4 shows a circular series of holes l2a so staggered and of suchsize that they, in the aggregate, make a completely circular draining zone in the toolwall. The aperture formations in the several disclosed patterns avoid the presentation of an opening which can be divided in two by a cross-section plane taken at any angle as to the axis of the tool; that is, the device presents trowelling area at every possible transverse section plane of the dehydrating zone. A large de-watering area is secured with a slight loss of trowel face on any cross-section plane.

What is claimed is:

l. A holl0w trowel for plastic bore face lining, having a body structure open at the rear end for drainage flow' and provided with a completely annular, water escape passage feature from the exterior face of the body to its chamber for rear flow.

2. The trowel of claim 1; the passage being characteristically of saw tooth interindented pattern.

3. A hollow trowel for plastering the bore face of a conduit, having a body structure of cylindrical sections open from end to end and provided with a water escape feature from the exterior face of the body to its interior and whichat every point in a peripheral zone will have an opening on sections taken longitudinally of the Wall of the body.

4. A trowel of the class disclosed and having a hollow, open rear end body structure having a peripherally complete de-watering crevice.

5. The trowel of claim 4; and which crevice is of sinuous outline.

6. The trowel of claim 4; and which crevice is 5 of saw-tooth outline.

'7. The trowel of claim 4; and in which the con tiguous edges of crevice are in relatively overhanging relation; the leading edge of the crevice overhanging the followingedge. 1 10 8. The trowel of claim 4; and in which the face of the trailing side of the crevice underlies the other side of the crevice to form a restriction.

.ing a cylindric, hollow body structure open from end to end provided with an aperture device which is effectively peripherally complete around the body to drain from its exterior into its cham- 9. A hollow trowel of the class described and 15 her.

having a body structure having a de-watering aperture the face of the trailing side of which is contiguous to and underlies the face or the opposite face.

HUBERT R. CRANE. 

